Vladimir Putin has launched a series of drone and missile attacks on Ukraine’s energy infrastructure in response to an Oct. 8 bridge bombing that damaged Russian supply lines. These attacks have left many Ukrainians without heat and electricity during the darkest and coldest period of the year.

CERL Advisory Council member Mary Ellen O’Connell told AP News:

“It is absolutely the case that terrorizing the civilian population, to break their morale, to get them to demand of their leaders that they surrender, is not a form of military necessity. Even if you’re attacking a military objective, if the intent in doing so is to terrorize civilians then you have committed a war crime.”

Mary Ellen O’Connell is the Robert and Marion Short Professor of Law and Research Professor of International Dispute Resolution—Kroc Institute for International Peace Studies, University of Notre Dame. Her work is in the areas of international law on the use of force, international dispute resolution, and international legal theory. Read her full bio here.